Method and apparatus for making a novel fabric

ABSTRACT

Method and apparatus for making a novel fabric in which a first and a second series of longitudinal threads are fed; threads of the second series are moved in a certain extension transversally to the threads of the first series; and each moved thread of the second series is interwoven with the respective thread of the first series changing the sense of movement of the threads of the second series in successive cycles in the fabric formation; the movement of the threads of the second series being effected by means of a complementary series of knitting machine needles inserted between conventional needles of a warp knitting machine which are moved apart from said conventional needles, then transversally moved and finally reinserted in a new location between said conventional needles.

United States Patent 1 Pascual [111 3,879,964 1451 Apr. 29, 1975 Salvatierra, 49, Tarrasa (Barcelona), Spain 221 Filed: July 18, 1912 2| Appl. No.: 273,018

[30] Foreign Application Priority Data July 19, 1971 Switzerland 010598/71 I 56] References Cited UNITED STATES PATENTS Stowe 66/192 Koppcnbcrg................'......... 66/193 Primary E.raminer-Ronald Feldbaum Attorney, Agent, or FirmWenderoth, Lind & Ponack [57] ABSTRACT Method and apparatus for making a novel fabric in which a first and a second series of longitudinal threads are fed; threads of the second series are moved in a certain extension transversally to the threads of the first series; and each moved thread of the second series is interwoven with the respective thread of the first series changing the sense of movement of the threads of the second series in successive cycles in the fabric formation; the movement of the threads of the second series being effected by means of a complementary series of knitting machine needles inserted between conventional needles of a warp knitting machine which are moved apart from said conventional needles, then transversally moved and finally reinserted in a new location between said conventional needles.

5 Claims, 14 Drawing Figures PATENTED 3,879,964 SHEET GIUF 12 PATENTEDAPRZSISYS 3.879.964

sum 03 0F 12 PATENTEmrnzsms SHEET [17UF 12 meminmzswvs 3,879,964 SHEET CBBF 12 SHEET CSOF 12 PmENIEmPmms METHOD AND APPARATUS FOR MAKING A NOVEL FABRIC This invention relates to fabric and to a method of and apparatus for producing the fabric.

As is already known the types or classes of fabric most used at present are warp and weft fabrics and mesh fabrics, each having advantages and disadvantages which make them suitable for specific uses.

The main characteristic of warp and weft fabric is its almost zero elasticity in either direction. It also allows for a large number of different weaves and combinations of colors with almost any yarn material, may be spun from either continuous or discontinuous fibres or filaments, and is used for a great variety of articles in almost all sectors of the textile industry.

However, because of the structure of the fabric and the limitations of weaving looms, it has not been possible, in spite of all efforts and technical progress as regards the speed of the machines, to achieve the rates of production and low costs required by current industrial, commercial and social developments.

With mesh fabrics, especially knitted fabrics, very acceptable production in terms of m /hour/machine, and low cost have already been obtained, and because of their ease of production, it is expected that such fabrics will be even more widely used in the near future, and that this will apply to all sectors of cloth production. However, these fabrics and the machines for producing them have many limitations or disadvantages; first, it is necessary to work with extremely regular and elastic spun yarn composed either of continuous threads, which limits their use to a few sectors, or discontinuous fibres, made from multi-ended threads, which are very costly and which often necessitate reducing the speed of the machines to limits which adversely affect their purpose and profitability. Second, although fabrics with considerably reduced elasticity can be made, in general their principal characteristic is that they have a high degree of elasticity in one or both directions, which is another obstacle to their use in many possible applications.

It is true that fabrics with characteristics similar to those of woven cloth or similar fabrics have recently been obtained on Ketten-Raschel machines, but this is always achieved using a conventional chain knitted structure as a support, with continuous thread materials being used normally on the back of the fabric and being linked on the right side of the fabric with other threads or materials made from discontinuous fibres, which give to the fabric a characteristic quality.

With special devices fitted to Ketten-Raschel machines, it has been possible to insert weft threads extending over the whole width of the fabric and arranged in a rectilinear manner parallel to each other, and it is these weft threads which give the finished fabric the required quality since these threads are linked to the base fabric by stitches or chain-stitches, the fabric usually being composed of very fine continuous threads which act as warps, resulting in an almost completely inelastic fabric. However, apart from the technical/mechanical difficulties of effective and regular insertion of the weft threads and the need for a very particular spun yarn material for each article, it is practically impossible to produce a patterned fabric; only plain material, more or less shiny, and with the appearance of a series of threads arranged side by side and in parallel, can be produced.

The present invention is intended to provide a fabric and a method of and apparatus for producing same, which combines the advantages of the two types of known fabric mentioned above, i.e. warp and weft fabric and mesh fabric, and more particularly chain knitted fabric, and which, besides being capable of a high rate of production similar to that of conventional knitted fabric, is practically inelastic in length or width, and which it is possible to produce in a wide variety of patterns and special efiects.

Another objective which can be achieved is that of being able to obtain a wide range of quality, appearance and feel as desired, varying from the most elementary elastic knitted fabric to the hardest or most inelastic warp and weft fabric, through all the intervening gradations.

The invention provides a fabric comprising a first series of theads which extend generally longitudinally of the fabric and serve as warps and a second series of threads which extend generally longitudinally of the fabric and are intercalated with threads of the first series, the threads of the second series each being displaced transversely with respect to said first series of threads first in one direction and then in the other direction so as to cross at least one of said first series of threads and form floats which extend transversely of the fabric and which serve as partial wefts, each of the threads of the second series being linked with a thread of the first series at each end of each float.

The invention also provides a method of forming the fabric, characterised by providing at least a first series of threads which extend generally longitudinally of the fabric in the manner of warps, and at least a second series of threads intercalated between the threads of the first series and extending generally longitudinally of the fabric; producing, in each successive fabric formation cycle, the displacement of at least one of the threads of the second series in a transverse direction relative to the first series of threads and to an extent corresponding to the space occupied by at least one of the threads of the first series, changing, in some of the fabric formation cycles, the direction of said displacements; and linking each thread of the second series, after each of the displacements, with the respective thread of the first series with which it coincides in its new position, the said displacements of the threads of the second series forming floats which extend transverse to the direction of the first series of threads, in the manner of multiple partial wefts.

In addition to the first series of threads and the second series of threads forming the transverse floats, a third series of generally longitudinally extending threads can be used, which are knitted and between whose stitches the other series of threads are intermingled and interlaced. Alternatively, the first series of intercalating them again between other threads of the first series; and of means for ensuring that the said threads of the second series are linked with the respective threads of the first series with which they coincide in their new position.

In a preferred embodiment, this apparatus can be used on a knitting machine of the Ketten or Raschel type, in which, in addition to the usual members for effecting knitting, there are also guide bars for feeding the first series of threads and the second series of threads which are to form the weft floats, means for transferring the second series of threads to additional needles interposed between the normal needles of the machine and forming a single alignment therewith but which, by means of a separating and transferring movement can change position relative to the said normal needles of the machine.

To summarize, the fabric, the method and the apparatus which are the subject of the present invention, exceed what is currently known about fabric manufacture, achieving the following advantages:

the resulting fabrics can have practically the same characteristics in respect of feel, elasticity, etc., as those manufactured on conventional warp and weft looms.

it is possible to choose the elasticity appropriate to each article for which the fabric is used.

a wide range of patterns can be obtained with a single machine without the need for long pattern chains, often substituting for the Jacquard apparatus which must be used with existing machines.

a rate of production or quantity of stitch courses per minute can be achieved which is not less than that obtained on current Ketten-Raschel machines.

the cost of the machines used is comparable to that of existing knitting machines (Ketten or Raschel).

the machine can be provided with devices whose process is the subject matter of one of our other patents, making possible the use of materials (wool, cotton, synthetic fibres, mixtures, etc.) of the same or lower quality as that of the single or multi-ended materials usually used with shuttle looms. Furthermore there is the great advantage of not needing to use for a single fabric different classes of material or thicknesses of thread which has been unavoidable to date in the many trials made with chain fit ting machines in order to obtain articles similar, to a greater or lesser extent, to drapery, covers, curtains, etc.

The invention is further described below with reference to the accompanying drawings, in which:

FIG. I is a schematic illustration of the basic structure of the fabric according to the invention;

FIG. 2 illustrates schematically the basic fabric of FIG. 1 combined with a traditional knit structure;

FIG. 3 is a variation of the fabric of FIG. 2;

FIG. 4 is another example ofa fabric according to the present invention;

FIGS. 5 to 9 schematically show a side view of the chain knitted structure (or knitted fabric or tricot (warp)) forming organs ofa Raschel chain knitting machine (or warp loom) along with the organs which form the novel fabric related to the invention, showing the successive phases of a complete fabric forming cycle.

FIGS. 10 to 14 are the prespective views of the same fabric organs shown in the FIGS. 5 to 9, showing the successive movements of said organs. In those FIGS.

the conventional sinkers 19) have been deleted for the sake of greater clarity in the drawings.

According to the invention the basic structure of the fabric shown in FIG. I, is obtained by having series of longitudinal warp like threads 1, which in the case of FIG. 1 are fixed i.e. are not moved, and a second series of longitudinal threads 2 intercalated between those of the first series. At each pick or cycle for producing the fabric, these threads 2 are displaced relative to the threads 1 to an extent corresponding to the space occupied by a given number of said warp like threads 1, which in FIG. 1 is three threads, and then said threads 2 are linked to the respective threads I with which they coincide after displacement, the direction of displacement of threads 2 alternating in successive stitch courses.

The threads 2, curing displacement, pass in front of some threads 1, as indicated at the points of intersection 3, and behind other threads I, as indicated at the points of intersection 4, in the manner of woven threads, and are linked to the threads 1 by closed stitches 5.

In this way, threads 2 form a series of floats 6, forming partial wefts, which are linked by their ends to their respective warp threads 1' and intercrossing with other intermediate threads 1, producing a fabric which can be totally inelastic due to the linking between said weft floats 6 and the warp like threads 1'.

Threads 2 forming the weft floats 6 can be arranged in equal or different numbers compared with those of warp threads 1 and can be distributed uniformly over the whole width of the fabric or be divided into separate groups which may be equal or different and whose density can vary at different areas of the width of the fabric.

Also, the transverse displacements of threads 2 can be equal for all the threads of all the stitch courses and change direction at each stitch courses, as in the illus trated examples where floats 6 are equal and uniformly distributed, or some threads 2 can be displaced on some stitch courses and other threads 2 on other courses. The extent of these displacements can be varied as can the direction of displacement after being displaced several stitch courses in the same direction.

It will therefore be understood that by combining threads of different thickness, colors and materials with these different working forms, it is possible to obtain a very large variety of patterns and effects.

Furthermore, the threads 1 and weft threads 2 forming the weft floats can be arranged intercalated between threads of another or other warps 7, which, as illustrated in FIGS. 2 and 3, form a conventional knit structure where each course or fabric formation cycle is effected during the corresponding formation cycle of the basic structure composed of threads 1 and 2, thus producing a compound fabric of which the first series of warp threads, i.e., I and 1' of the basic fabric shown in FIG. 1, are intercalated between the stitches 8 formed by the warp threads 7 of this third series which form the knit structure, and whose threads 2 forming the warp floats of the basic fabric, beside intercalating with threads 1' of the first series as in FIG. 1, intercalate with stitches 8 of the fabric formed by the third series of threads 7.

Because of the large number of intercalation points between all the threads in the composite fabric thus obtained, there is no need to cross the weft threads 2 when linking them to threads I so as to form closed stitches 5 as previously stated. Instead, the link between the weft threads 2 and their corresponding threads 1' can be effected using a simple open loop 9, in the manner illustrated in FIG. 3.

Another possible variation of the fabric, as illustrated in FIG. 4, can be obtained by combining into one series the first and third series of warp threads 1-] and 7, i.e., warp knitting the threads 7 and using these as threads 1, l, the threads 2 forming the weft floats 6 being linked with some of the knitted threads 7 by means of stitches 5 which intercalate with stitches 8 of the knitted threads 7.

It is easy to understand the very considerable possibilities for variation of the basic fabric which we have just described and to this can be added variations arising from the large number of conventional knit structures which can be combined with the said basic fabric, from which it can be inferred that the variations obtainable with different combinations of weaves of one or another fabric, fibre material, colour, etc., are practically limitless.

For the manufacture of fabric of the present invention using the method according to the invention, a chain knitting machine may be used, in which, in addition to the warp threads which are knitted normally, there are fed, using corresponding guide bars, the series of fixed warp threads, and the series of threads forming the weft floats, which latter threads are supplied to a corresponding number of additional needles intercalated between the normal needles of the machine and in alignment with them, but which, by means of a separation and transfer movement, can change position relative to said normal machine needles, this transfer being effected after the guides for the threads to be knitted have deposited those threads in the normal needles of the machine and the guides for the weft threads have deposited their threads in the said movable needles.

The apparatus for making the novel fabric, related to the invention, comprises means for feeding said first and second series of inserted longitudinal threads, means for engaging each of the threads of the second series, separating them from the threads of the first series, displacing them transversely to a predetenninecl extent with respect to the threads of the first series and reinserting them in a new location between the threads of the first series, and also means for linking the threads of the second series with the respective threads of the first series with which they coincide in their new position.

Said means for feeding the threads of the first series may be either stationary or movable in cooperation with means for forming with at least some of the threads of the first series a conventional chain knitted structure (or knitted fabric warp).

Furthermore, the apparatus may be combined with third feedingmeans for feeding a third series of longitudinal threads inserted between the threads ofthe first and second series and means for forming with said threads of the third series a conventional chain knitted structure, all said means bieng synchronously operated in each fabric forming cycle.

In a preferred embodiment said third feeding means for feeding a third series of longitudinal threads and said means for forming with the threads of the third series a chain knitted structure consist of at least one guide bar and at least one needle bar of a conventional chain knitting machine (or warp loom) such as a Ketten or Raschel type machine, and the apparatus which is the subject of the invention comprises in said conventional chain knitting machine (or warp loom) a first complementary guide bar for feeding the threads of the first series, at least a second complementary guide bar for feeding the threads of the second series, both first and second complementary guide bars being adjacent to the guide bars of the conventional chain knitting machine (or warp loom), and at least one complementary needle bar adjacent to the conventional needle bar of the machine, the needles of said complementary needle bar being adapted to be inserted between the needles of said conventional needle bar and in alignment with said needles of the conventional needle bar.

The guide bar or guide bars and the needle bar or needle bars of the conventional chain knitting machine (or warp loom) are provided with corresponding driving means to impart to them the necessary movements to knit a conventional knitted fabric (warp). The complementary needle bar of the apparatus which is the subject of the invention is, in turn, provided with driving means in order to impart it a rising movement, a forward movement by which the needles of this complementary needle bar become detached from the needles of the conventional needle bar of the chain knitting machine (or warp loom), a lateral translatory movement the extent of which corresponds to the space occupied by a predetermined number of needles of said conventional needle bar, a backward movement by which the needles of the complementary needle are again inserted between the needles of the conventional needle bar to come into a new position resulting from the lateral displacement movement of the complementary needle bar, said driving means of the complementary needle bar being synchronised with the driving means of the conventional needle bar of the chain knitting machine (or warp loom) so that the rising and descending movements of the complementary needle bar are simultaneously effected together with the rising and descending movements of the conventional needle bar during the formation of each stitch course or fabric forming cycle.

The second guide bar of the apparatus, the subject of the invention, is also provided with driving means which impart to them an oscillating forward to backwards and lateral movement so that each one of the guides of this second bar deposits the corresponding thread into the book of each one of the needles of the complementary needle bar at the same time as the conventional guide bars deposit their threads into the needles of the needle bar or needle bars of the chain knitting machine (or warp loom).

Lastly, the first guide bar of the apparatus which is the subject of the invention is, in turn, provided with driving means to impart the guides of the same with an oscillating forward to backwards and lateral movement in order to interlace each one of the respective threads of the first series with the corresponding thread of the second series after the achievement of the lateral displacement of the apparatuss complementary needles bar. In these FIGS. 17 denotes the normal needle bar of a Raschl machine having a single needle bar, the needles 16 of which are adapted to move with a rising and a dfl'scending motion between the knockover blades mounted in the fixed knockover comb 28 of the machine. This Raschel machine further comprises a series of sinkers 19 mounted in the corresponding sinker bar (not shown). The sinkers 19 of this sinker bar travel back and forth between the needles l6 i.e., above the knockover blades 18, and the upper part of the machine comprises two guide bars (10) and (11) which carry two series of guides (12) and (13), respectively, which hand over the needles (16) the two warp thread series (14) and (15) with which the Raschel machine knits a conventional chain knitted structure (or knitted fabric (warp)).

The apparatus related to the invention comprises a complementary needle bar (24) located in front of the conventional needle bar (17) of the Raschel machine, a first additional guide bar (20) located in front of the guide bar (11) of the Raschel machine and a second additional guide bar (21) located in front of the first guide bar (20).

The guide (22) of the first guide bar (20) feed a first series of fixed threads (1) of the novel fabric, and the guides (23) of the second guide bar (21) of the apparatus feed a second series of threads (2) of the novel fabric, and both guide bars (2) and (21) are provided with actuating means which impart to them a forward and backward oscillating movement concurrent with the motion of conventional guide bars (10) and (11) of the Raschel machine as well as lateral oscillating movements analogous to the oscillating movements of the conventional guides bars (10) and (11).

The complementary needle bar (24) of the apparatus carries a series of needles (25) which are shaped in the form of an elbow (elbowed) so that they can remain inserted between the needles (16) of the conventional needle bar (17) of the Raschel machine and totally in line with said needles (16). Said complementary needle bar (24) of the apparatus is provided with driving means which impart to it a rising and descending movement complementary with the motion of conventional needle bar (17) of the Raschel machines backward and forward displacement movements in order to separate its needles (25) from the needles (16) of the conventional needle bar (17), lateral displacement movements to the one or other side, the extent of which is variable corresponding to the space occupied by several of the needles (16) of the conventional needle bar (17), and forward to backwards movements to reinsert its needles (25) between the needles (16) of the conventional needle bar (17).

The above-cited driving means of the guide bars (20) and (21) and of the complementary needle bar (24) of the apparatus are neither described not illustrated in the drawings because they form no part of the invention and because they may consist of conventional type mechanisms such as those used for anlaogous purposes in conventional knitting machines.

At the start of each one of the forming cycles of the novel fabric the elements hereinbefore described are located in the positions illustrated in FIGS. 5 and 10 where the needles (25) of the complementary needle bar (24) are in line with the needles (16) of the conventional needle bar (17) and all the needles (25) and (16) are in a low position between the blades (18) of the knockover comb (28) of the machine, the meshes of the last stitch course of the fabric (26) being held in the hooks of the needles (16), while the ensemble of the guide bars (10), (11), (20) and (21) are located behind the plane determined by the needles (16) and (25).

in the first fabric formation phase the two needles bars (17) and (24) simultaneously effect rising movements whereby all the needles (16) and (25) are raised until they protrude above the ends of the knockover blades (18) and at the same time the sinkers (19) move backwards and becoming positioned between the needles in order to retain the thread and compelling the meshes of the last stitch course of that fabric to open the latches of the needles (16) and slip along the stems of these needles (16) from which the fabric comes to rest suspended, as it is seen in the FIG. 6.

As a next step, while the sinkers (19) move forward thereby withdrawing from between the needles. the ensemble of the guides bars (10), (11), (20) and (21) swing forward (see FIG. 7), the guide bars (10) and (11) effect a lateral oscillation so that their guides deposit the threads (14) and (15) into the hooks of the needles (16) of the conventional needle bar (17) in the way used for forming the chain knitted structure (or knitted fabric (warm), and the second guide bar (21) of the apparatus swings laterally in turn, so that its guides (23) deposit the threads (2) of the second series of longitudinal threads into the hooks of the needles (25) of the complementary needle bar (24) as shown in FIGS. 8 and 11. In this phase the first guide bar (20) also effects a lateral oscillation in order to interlace the first series of threads (1) which pass through their guides (22) with the threads (2) which had been deposited during the foregoing stitch course as will be explained later on.

In the following phase the guide bars (10), (11), (20) and (21) swing together backward as shown in FIG. 9, and the complementary needle bar (24) moves forward (see FIGS. 9 and 12) so that its needles (25) are separated from the needles (16) of the conventional needle bar (17) and it is then shifted aside (in FIG. 13 it is shown in a position where it is being shifted towards the left of the Figure) whereby its needles (25) drag in the respective threads (2) which in FIGS. 10 and 14 are represented by dotted lines for the sake of clarity, the extent of this lateral displacement of the complementary needle bar being such that it corresponds to the space occupied by several of the needles (16) of the conventional needle bar (17). in the instance shown this lateral displacement coincides with the space occupied by three needles (16) to form a fabric such as shown in the FIG. 3.

The complementary needle bar (24) then moves backwards until its needles (25) are again inserted between the needles (16) of the conventional needle bar, but in a new position with respect to these same nee dles, i.e., the needle (25) occupies the position previously occupied by the needle (25'), the needle (25') occupies the position previously occupied by the needle (25 and so on. Lastly, the two needle bars (24) and (17) descend together whereby all the needles (25) and (16) are again aligned in the low position between the knockover blades (18), thereby forming the portions of the threads (2) comprised between the two new successive positions of the respective needles (25 (25), (25"), etc., and forming the floating threads (6) which come to be interlaced at their ends with the corresponding threads (I) owing to the movement of the guides bar (20), as mentioned above.

In the fabric forming cycle the complementary needle bar (24) may shift laterally to the left, or may shift to the right. ln the formation of the fabric shown in the FIG. 3 this displacement will be made, as is selfexplanatory, in a direction opposite to the foregoing cycle, i.e., towards the right to the same extent corresponding to the space occupied by three of the needles (16) of the conventional needle bar (17). In this displacement the hooks of the needles (25) will slip along the floating threads (6) of the threads (2) formed in the foregoing cycle, and in this new fabric forming cycle the floating threads (6) will be interlaced with the meshes of the new stitch course.

It is obvious that the movements of the needles (25) may be made when all the needles (25) and (16) are in the low position as well, instead of making them as described when the needles are in the raised position. That is, that after all the needles (l6) and (25) have come up and the threads (14) and (15) have been deposited into the hooks of the needles (l6) and the threads (2) have been deposited into the hooks of the needles (25), as shown in the FIG. 11, all the needles can be caused to descend to the position shown in FlG. then the complementary needles shown in FIG. 10 of the complementary needles bar (24) may perform a forward, lateral displacement and backwards movemerit in an analogous way to the manner previously described with reference to FIGS. l2, l3 and 14, except that the needles (16) and (25) will be in the low position shown in the FIG. 10.

I claim:

1. ln a warp knitting machine comprising at least one guide bar which feed and guide warp threads which are to form the warp knit fabric and at least one knitting machine needle bar, the arrangement comprising:

at least a first and second complementary guide bar said bars synchronized with the guides feeding the warp threads, for feeding respectively a first and a second series of longitudinal warp-like threads and for guiding said longitudinal threads and inserting them between the warp-like threads which form the warp knit fabric;

at least one complementary needle bar having needles similar to knitting machine needles, synchronized with the needles of the machine and operatively positioned to be inserted between the conventional needles of the machine;

complementary operating means coupled to said complementary needle bar for separating the needles thereof from the conventional needles of the machine, moving said complementary needles transversely to the conventional needles of the machine and reinserting said complementary needles at a new location between said conventional needles; and

complementary operating means operatively positioned for moving said complementary first and second guide bars in such a manner that the threads of said second series are wound around the respective threads of said first series.

2. The apparatus of claim 1 wherein said complementary needle bar is divided in several groups of needles and further comprising means operatively disposed to operate each of said needle groups independently from the others.

3. The apparatus of claim I further comprising means operatively positioned to individually operate each needle of said complementary needle bar.

4. The apparatus of claim 2 comprising means operatively positioned for selecting the groups of complementary needles which are to be operated at each working cycle of the machine.

5. The apparatus of claim 3 comprising means operatively positioned for selecting the individual needles which are to be operated at each working cycle of the machine. 

1. In a warp knitting machine comprising at least one guide bar which feed and guide warp threads which are to form the warp knit fabric and at least one knitting machine needle bar, the arrangement comprising: at least a first and second complementary guide bar said bars synchronized with the guides feeding the warp threads, for feeding respectively a first and a second series of longitudinal warp-like threads and for guiding said longitudinal threads and inserting them between the warp-like threads which form the warp knit fabric; at least one complementary needle bar having needles similar to knitting machine needles, synchronized with the needles of the machine and operatively positioned to be inserted between the conventional needles of the machine; complementary operating means coupled to said complementary needle bar for separating the needles thereof from the conventional needles of the machine, moving said complementary needles transversely to the conventional needles of the machine and reinserting said complementary needles at a new location between said conventional needles; and complementary operating means operatively positioned for moving said complementary first and second guide bars in such a manner that the threads of said second series are wound around the respective threads of said first series.
 2. The apparatus of claim 1 wherein said complementary needle bar is divided in several groups of needles and further comprising means operatively disposed to operate each of said needle groups independently from the others.
 3. The apparatus of claim 1 further comprising means operatively positioned to individually operate each needle of said compleMentary needle bar.
 4. The apparatus of claim 2 comprising means operatively positioned for selecting the groups of complementary needles which are to be operated at each working cycle of the machine.
 5. The apparatus of claim 3 comprising means operatively positioned for selecting the individual needles which are to be operated at each working cycle of the machine. 